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b=c4GWBpvzfnCz9lE8EK3nyqPQ03jCrZtPK9JhbfcF8uTrBCPiiSm9NO6ErwC0ZIYtW10thuSYfj3N9Dp7IQ119DePIl3/RQnwYH+fT5V2H7R4kw7SPVvMLnBcog/asN4Bn3IFqsyi6SsuDaoOM69udurejbpGHK/9jMoUoYktiK0= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL1PR12MB5320.namprd12.prod.outlook.com (2603:10b6:208:314::17) by DSWPR12MB999153.namprd12.prod.outlook.com (2603:10b6:8:36e::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.315.13; Wed, 12 Aug 2026 22:28:56 +0000 Received: from BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1]) by BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1%5]) with mapi id 15.21.0315.012; Wed, 12 Aug 2026 22:28:56 +0000 Message-ID: <521ef280-e311-4949-b520-fc4e78b67206@amd.com> Date: Wed, 12 Aug 2026 17:28:52 -0500 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND PATCH v4 06/15] fs/resctrl: Introduce resctrl_set_kmode_support() to initialize supported modes To: Reinette Chatre , Babu Moger , corbet@lwn.net, tony.luck@intel.com, Dave.Martin@arm.com, james.morse@arm.com, tglx@kernel.org, bp@alien8.de, ben.horgan@arm.com, fenghuay@nvidia.com Cc: skhan@linuxfoundation.org, x86@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, akpm@linux-foundation.org, rdunlap@infradead.org, peterz@infradead.org, feng.tang@linux.alibaba.com, dapeng1.mi@linux.intel.com, elver@google.com, enelsonmoore@gmail.com, kuba@kernel.org, ebiggers@kernel.org, lirongqing@baidu.com, seanjc@google.com, nikunj@amd.com, xin@zytor.com, pawan.kumar.gupta@linux.intel.com, tiala@microsoft.com, chang.seok.bae@intel.com, kprateek.nayak@amd.com, prathyushi.nangia@amd.com, kim.phillips@amd.com, naveen@kernel.org, darwi@linutronix.de, elena.reshetova@intel.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.lendacky@amd.com, eranian@google.com, peternewman@google.com, qinyuntan@linux.alibaba.com References: <681e0257-80e0-44c3-b826-20e314a3eb0d@intel.com> Content-Language: en-US From: "Moger, Babu" In-Reply-To: <681e0257-80e0-44c3-b826-20e314a3eb0d@intel.com> Content-Type: text/plain; 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Sure. > >> they support before generic resctrl exposes those policies through the > > "policies" -> "modes" > (this is related to the earlier "use consistent terminology comment" I > will stop highlighting instances) Sure. > >> filesystem. >> >> Add the `struct resctrl_kmode_cfg` to define the default mode statically, >> and introduce `resctrl_set_kmode_support()` so architecture code can >> register supported kernel-mode policies during resctrl initialization. The >> `INHERIT_CTRL_AND_MON` policy is supported by default, so architectures >> only need to register any additional modes. > > Please keep changelog high level and not describe the code that can be seen from patch. > When doing so, please write in imperative tone. Yes. > >> >> Signed-off-by: Babu Moger >> --- >> v4: New patch to initialize supported kernel-mode's. >> https://lore.kernel.org/lkml/737a4228-52fb-4583-ac64-8efe79c107e6@intel.com/ >> Changed the kmode_cur to enum resctrl_kernel_mode in resctrl_kmode_cfg. >> Moved the resctrl_kmode_cfg to filesystem code. >> --- >> fs/resctrl/internal.h | 12 ++++++++++++ >> fs/resctrl/rdtgroup.c | 23 +++++++++++++++++++++++ >> include/linux/resctrl.h | 10 ++++++++++ >> 3 files changed, 45 insertions(+) >> >> diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h >> index 48af75b9dc85..178126bb2da5 100644 >> --- a/fs/resctrl/internal.h >> +++ b/fs/resctrl/internal.h >> @@ -314,6 +314,18 @@ struct mbm_state { >> u32 prev_bw; >> }; >> >> +/** >> + * struct resctrl_kmode_cfg - Kernel-mode policy snapshot from architecture > "policy snapshot"? what does this mean? This is not just from architecture either. struct resctrl_kmode_cfg - Resctrl kernel mode support and active state > >> + * @kmode: Bitmap of supported &enum resctrl_kernel_mode values. Each >> + * supported mode is represented by BIT(mode). >> + * @kmode_cur: Currently selected kernel-mode policy. > > How about "Active kernel mode"? Sure. > >> + * @k_rdtgrp: Resource group backing global-assign modes when applicable; > > (stray semi-colon) Ack. > >> + */ >> +struct resctrl_kmode_cfg { >> + unsigned long kmode; > > How about "kmode_sup" to complement the "kmode_cur"? Sure. > > To make it obvious this is a bitmap you can use something like: > DECLARE_BITMAP(kmode_sup, RESCTRL_NUM_KERNEL_MODES) Sure. If the code remains same. > > >> + enum resctrl_kernel_mode kmode_cur; >> + struct rdtgroup *k_rdtgrp; >> +}; >> extern struct mutex rdtgroup_mutex; >> >> static inline const char *rdt_kn_name(const struct kernfs_node *kn) >> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c >> index cc9966ff6cdf..0ee0dfaf9065 100644 >> --- a/fs/resctrl/rdtgroup.c >> +++ b/fs/resctrl/rdtgroup.c >> @@ -78,6 +78,16 @@ static void mon_put_kn_priv(void); >> >> struct dentry *debugfs_resctrl; >> >> +/* >> + * Global kernel-mode resctrl policy. Architectures add supported modes before >> + * resctrl is mounted; @kmode_cur tracks the active policy after user selection. > > ah - above it is referred to as "active". I find "active" to be more descriptive than > "selected" as highlighted above. The "after user selection" seems distracting. > "@kmode_cur is the active kernel mode" is all that is necessary, no? Sure. > >> + */ >> +static struct resctrl_kmode_cfg resctrl_kcfg = { >> + .kmode = BIT(INHERIT_CTRL_AND_MON), >> + .kmode_cur = INHERIT_CTRL_AND_MON, >> + .k_rdtgrp = NULL >> +}; > > This initialization needs to be reconsidered to take into account that system may not > support allocation or monitoring. > Yes. We may need to change it to dynamic initialization than static. Thanks Babu